Safety operating device for punch presses and the like



S. J. MILLER Jan. 11, 1955 SAFETY OPERATING DEVICE FOR PUNCH PRESSES AND THE LIKE Filed July 30, 1952 2 Sheets-Sheet l ATTORNEY Jan. 11, 1955 s. J. MILLER 2,699,241

SAFETY OPERATING DEVICE FOR PUNCH PRESSES AND THE LIKE Filed July so, 1952 2 Sheets-Sheet 2 INVENTOR ATTORNEY United States Patent SAFETY OPERATING DEVICE FOR PUNCH PRESSES AND THE LIKE Stephen J. Miller, Chicago, Ill. Application July 30, 1952, Serial No. 301,627 4 Claims. (Cl. 192-131) This invention relates to improvements in safety operating devices for punch presses and the like, and particularly to a device of this character intended and constructed for two-hand operation.

In the use of punch presses and drop hammers and the like, where work is manually handled and fed to and removed from the machine, there is great danger of injury to the hands of the operator. This is especially true where the machine is being operated on a piecework production basis, as the operator may attempt to speed production by feeding and removing the material with one hand while operating controls with the other hand. To avoidthis, it has been the practice to provide machines with operating controls serving as safety devices requiring the operator to hold the operating controls with both hands to thus endeavor to assure that both hands will be away from the operating parts of the machine. However, in some instances such two-handed safety devices have been rendered ineffective by reason of the fact that the operators have resorted to subterfuges or cheating such as tying down one operating handle or operating part and thus leaving the operator free to use one hand exclusively for feeding and removing the work, while controlling the machine through use of the other hand.

It is an object of this invention to provide a safety operating device for punch presses and the like requiring two-hand operation, and with the parts so constructed that any attempt to tie down or otherwise put one control handle or lever in inoperative position will render the entire device inoperative.

Another object is to so construct the parts that both manually operated handles or hand levers must be ac tuated together and substantially in unison to accomplish connection of a clutch or other machine operating mechanism.

Yet another object is to provide mechanism of this character that can be installed upon and can be used as an operating control for substantially any and all punch presses and drop hammers and other like machines, and which can be adjusted to change and vary the sensitivity of operation of the hand levers or handles.

With the above and other objects in view, some of which will be apparent to those skilled in the art, and others of which are inherent in the construction and operation of the mechanism, my invention includes certain novel features of construction and association of parts, which will be hereinafter set forth in connection with the drawings.

In the drawings:

Figure 1 is a view in front elevation of a device embodying my invention with a cover removed to better show construction and association of the parts.

Fig. 2 is a view similar to Figure 1 showing the parts in the inoperative relation.

Fig. 3 is a transverse sectional view substantially on line 33 of Figure 1 Fig. 4 is a view similar to Fig. 2 illustrating the trip ping and inoperative position of the parts when only one handle or hand lever is actuated.

Fig. 5 is a view similar to Figure 1 showing a slightly modified arrangement of the parts rendering the device more sensitive.

Fig. 6 is a fragmentary vertical sectional view substantially on line 6-6 of Figure 1.

Fig. 7 is a fragmentary elevational view showing the operating cam in the adjustment and relation disclosed in Fig. 5.

Fig. 8 is a perspective view of the operating cam.

Fig. 9 is a fragmentary view on a reduced scale illustrating portions of a punch press or like machine having my invention applied thereon.

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Fig. 10 is a fragmentary transverse sectional view and top plan to better disclose the parts illustrated in Fig. 9.

The box or case 1 can be made of sheet metal or other suitable material, and this preferably constitutes a back 2 of substantially rectangular shape enclosed by outstanding side walls 3 and 4 and top and bottom walls 5 and 6. It is perhaps preferable that a. mounting or supporting plate 7 be provided on the inner side of the back plate or wall 2 of the box or case, and that the forward side of the box or case be open to permit access to the interior thereof. However, to prevent tampering with or damage to parts within the box or case 1, a cover 8 is provided to close the outer open side.

This box or case is to be mounted upon the frame or supporting structure of a punch press of the general character indicated at A in Fig. 9, and mounting brackets 9, 10, 11 and 12 are provided to outstand from the side walls 3 and 4 and are provided with openings 13 to receive screws 14, or other suitable fastenings, by which the box will be held in place upon and keep rigidly mounted upon the supporting frame of the power press A.

The power press or other machine with which the device of my invention is to be used has two operating handles or levers B and C spaced apart somewhat after the manner disclosed in Fig. 10, to thus be disposed on opposite sides of the machine and away from working or punching parts thereof so that the operator of the machine can conveniently actuate these handles or levers with the two hands and with the hands and wrists and forearms completely spaced from working parts of the machine and consequently in such location that there is no possibility of the working parts causing injury to any part of the hands.

This invention includes parts within the box or case 1 to be operated by manual actuation of the operating handles or levers B and C, and to impart operating movement to a clutch or other means by which the machine A is rendered operative. As here illustrate-d, I have not disclosed any particular construction of punch press or other machine, and have not disclosed a clutch or other mechanism, since such machines and controls therefor are well known in the art. The throwing in of a clutch or other control means for the machine A is accomplished through pulling force exerted upon clutch or other actuating parts, all of which are well known, and with my device this pulling movement is initiated and is carried through by twohanded operation of the operator in moving the control handles or levers B and C in unison.

A pull operating bar 15 is slidably mounted through '1 rectangular opening provided in the bottom wall 6 of the box or case 1, with its lower end projecting downwardly, and a cylindrical portion 16 is provided at the upper end of this pull operating bar 15 and is endwise slidably received through a bearing opening in the top wall 5 of the box or case. A compression coil spring 17 is fitted around the cylindrical portion 16 on the upper side of the top wall 5, and is held in place by a nut 18. By this arrangement, the pull operating bar 15 is normally held in substantially the position illustrated in Figure l.

A similar pull operating bar 19 is slidably mounted through a rectangular opening in the bottom wall 6, in a location spaced from the pull operating bar 15, and has a cylindrical upper portion 20 slidably received through a bearing opening in the top wall 5. A coil spring 21 is fitted on this cylindrical portion 20 and is held in place by nut 22. The pull operating rods 15 and 19 have openings 23 and 24 through the lower extending ends thereof and pull links 25 and 26 are connected in these openings and are suitably connected to have pulling force applied thereto through the handles or levers B and C. When the two levers B and C are operated together, the pull operating rods 15 and 19 will be moved downwardly substantially in unison, and when a single handle or lever is operated the pull operating bar connected therewith will be moved downwardly and the remaining pull operating bar will be held in its upper position by the coil spring.

A machine control operating bar 27 is slidably mounted through a substantially rectangular bearing opening in the top wall 5, and is provided with a cylindrical portion 28 at its lower end which is slidably mounted through a suitable bearing opening in the bottom wall 16. Th1s machine control operating bar 27 is disposed substantially centrally between the pull operating bars 15 and 19, and a coil spring 29 is fitted around the cylindrical portion between the upper face of the bottom wall 6 and a shoulder at the lower terminus of the rectangular body of the operating bar 26, a nut 30 being provided on the outer side of the bottom wall 6 to stop upward movement of this machine control operating bar 27, under the pressure exerted by the spring 29. At its upper end, the bar 27 has an opening 31 through which a machine control operating link 32 is connected.

Bearing rolls 33 and 34 are mounted on the mounting or supporting plate 7 adjacent to the outer sides of the pull operating bars 15 and 19, and the machine control operating bar 27 has a roller 35 thereon which operates and functions somewhat after the manner of a centering member. This bar 27 has a cam or lug portion 36 fixedly mounted thereon at a location spaced from and below the roller 35, and this cam or lug portion is provided with a substantially flat bearing face on its upper side. Operating dogs 37 and 38 are swingably mounted on the upper portions of the pull operating bars 15 and 19, by bearing screws 39 and 40, and on their lower adjacent faces are provided with diagonal or oblique faces 41 and 42. Leaf springs 43 and 44 are fixedly mounted at one end on the pull operating bars 15 and 19, and have their upper ends bearing resiliently against the outer sides of the operating dogs 37 and 38 so that the operating dogs are normally resiliently urged to substantially the position shown in Figure 1.

As stated, the pull operating bars 15 and 19 are connected through links 25 and 26 to the handles or operating levers B and C, so that these pull operating bars can be pulled down or depressed against the force of springs 17 and 21 by manipulation of the handles or levers B and C; and, the machine control operating bar 27 is connected through machine control operating link 22, to a control clutch or other control means for a punch press or other machine with which my invention is used.

When a single handle or lever B or C is actuated, the

parts will assume substantially the position shown in Fig. 4, where the dog 38 of the depressed pull operating bar 19 has ridden across the upper face of the cam or lug 36 and has swung up to press its lower end against the diagonal face of the operating dog 37 and laterally displace this dog 37 so that it cannot bear against the upper face of the operating cam or lug 36. It will be appreciated that when one handle or lever B or C is operated, the device is completely inoperative, and the device is thus rendered completely inoperative to control the machine clutch or other operating control part.

As stated, operators have in some instances endeavored to tie down or permanently depress one hand lever B or C and to operate the control with a single hand lever; and, in Fig. 2 it may be assumed that the handle or lever connected with the pull operating bar has been tied down, and that the operator has endeavored to then accomplish operative control through the pull operating bar 15, and the relative position of the parts is clearly illustrated as being such that the two dogs are inoperative.

When the two handles or levers B and C are operated in unison, the leaf springs 43 and 44 exert pressure against the outer sides of the swinging lower ends of the operating dogs 37 and 38, and the diagonal faces 41 and 42 are thus brought into contact and the operating dogs are held in position to exert downward pressure and pulling force upon the upper face of the cam or lug portion 36 so that the machine control operating bar 27 is pulled downwardly against the expansion force exerted by spring 29 and pulling force is imparted through the link 32 to the operated control part of the machine.

As illustrated in Figs. and 7, the cam or lug part 36 is made narrower on one end than on the other, and by reversing this lug in the manner shown the sensitivity of the control is increased. A clamp screw 45 is provided so that the cam or lug portion 36 can be readily reversed.

From the foregoing, it will be seen that I have provided a safety operating device for punch presses and the like in which it is impossible to tie down or otherwise render one control inoperative and then to accomplish control through a single part.

While I have herein shown and described only certain specific embodiments of my invention and have set forth only possible modifications, it will be appreciated that many changes and variations can be made in the form and construction of the parts without departing from the spirit and scope of my invention.

I claim:

1. A safety operating device for punch presses and the like comprising a casing having top and bottom walls, a pair of spaced apart pull operating bars slidably mounted through openings in the top and bottom walls and having their upper and lower ends extending beyond the casing, springs on the upper ends of the pull operating bars normally resiliently acting to dispose the lower ends of said pull operating bars in elevated position, a machine control operating bar slidably mounted through the top and bottom walls of the casing between said pull operating bars, a spring normally resiliently holding said machine control operating bar with its upper end elevated, operating dogs swingably mounted on the upper portions of the pull operating bars within the casing, springs normally urging said operating dogs to swing inwardly, a cam portion fixedly mounted on the machine control operating bar below the normal position of the operating dogs when swung inwardly, and means to independently pull down the pull operating bars, said operating dogs being of sufficient length that when only one pull operating bar is pulled down the dog thereon will contact the cam portion and will swing against the opposite operating dog to displace said opposite dog from contact with the cam portion.

2. A variable safety operating device for punch presses and the like comprising a casing, a pair of pull operating bars slidably mounted in said casing, a machine control operating bar slidably mounted in the casing intermediate said pull operating bars, operating dogs swingably mounted on the upper portions of the pull operating bars within the casing, springs urging the swinging ends of said operating dogs inwardly, a cam portion having at least two cam faces of different width reversibly and fixedly mounted on said machine control operating bar to bring a selected cam face into operative position, and means securing said cam in position to be engaged by said operating dogs.

3. A safety operating device for punch presses and the like comprising a casing having top and bottom walls, a pair of spaced apart pull operating bars slidably mounted through openings in the top and bottom walls and having their upper and lower ends extending beyond the casing, compression springs acting between the upper ends of the pull operating bars and the upper side of said top wall normally resiliently acting to dispose the lower ends of said pull operating bars in elevated position, a machine control operating bar slidably mounted through the top and bottom walls of the casing between said pull operating bars, a compression spring acting between said machine control operating bar and the upper side of said bottom wall normally resiliently holding said machine control operating bar with its upper end elevated, operating dogs swingably mounted on the upper portions of the pull operating bars within the casing, springs normally urging said operating dogs to swing inwardly, a cam portion fixedly mounted on the machine control operating bar below the normal position of the operating dogs when swung inwardly, and means to independently pull down the pull operating bars, said operating dogs being of sufficient length that when only one pull operating bar is pulled down the dog thereon will contact the cam portion and will swing against the opposite operating dog to displace said opposite dog from contact with the cam portion.

4. A safety operating device as in claim 3, in which said pull operating bars are provided with upwardly facing shoulders spaced from said upper ends and adapted to engage with the lower side of said top wall to limit upward movement of said operating bars.

ReferencesCited in the file of this patent UNITED STATES PATENTS 1,190,900 Hoffman July 11, 1916 1,429,468 Verdin Sept. 19, 1922 2,301,817 Rusch Nov. 10, 1942 2,463,515 Buffardi Mar. 8, 1949 

